Study On Improvement In The Solubility And Emulsifying Properties Of Wheat Gluten By Enzymatic Modification

The wheat gluten powder as a quality protein rich resources has been used in theproduction of food industry. However, as its poor solubility and emulsifying properties, thescope of application of wheat gluten has been limited. At present, the methods ofmodification are as followed: the physical method, the chemical method and the enzymemethod. In this research, the enzyme hydrolysis ability for wheat gluten enzymaticmodification was selected. The solubility and emulsifying properties of wheat gluten wereimproved. Meanwhile, the modified effects the substrate concentration, the dosage ofenzyme, time, pH and temperature brought to the solubility and emulsifying propertieswere analyzed, also, the process conditions were optimized; and the modified wheat glutenwas mixed with the flour to make a bread baking test, and the results of the test wereconcluded as followed:(1) Protemax protease could improve the degree of hydrolysis of wheat glutenUsing the neutral protease, alkaline protease, flavor protease, pepsin and protemaxprotease to hydrolyze the wheat gluten separately, the following results showed: the thehydrolysis degree of wheat gluten hydrolyzed by protemax was bigger than hydrolyzed byothers, the molecular weight after hydrolyzed is smaller, and the subsequent proteinrecovery rate is bigger. Therefore the protemax was chosen as the subsequent modifiedenzyme for wheat gluten.(2) The optimum technological conditions to enhancing the solubility properties ofwheat gluten by enzyme method were obtained.Using the protemax protease to hydrolyze the wheat gluten, each factors couldenhance the emulsifying properties of wheat gluten in different ways. According to thesignificant influence of different factors on hydrolysis of wheat gluten, the order of thefactors were pH, substrate concentration, reaction time, the dosage of enzyme. The bestmodification process through response surface experiments was that concentration ofsubstrate8.21%, reaction time3.47hours, dosage of enzyme1203U/g and pH6.4in thecontext of50℃. Its protein dispersion index could reach32.73%.(3) The optimum technological conditions to enhancing the emulsifying properties ofwheat gluten by enzyme method were obtained. Those factors to improve the emulsifying properties of wheat gluten included thedosage of enzyme, substrate concentration, time and pH. The best modified process byresponse surface was that concentration of substrate8%, reaction time3.5hours, dosageof enzyme1210U/g and pH6.5under the50℃. Its emulsifying ability index and theemulsifying stability index could reach94.5mL/g and30.42min.(4) The modified wheat gluten could have influence on low gluten flour dough andprocessing quality of breadThe two kinds of wheat gluten by modified and unmodified were compared throughbread baking. The conclusion indicated that the bread with modified wheat gluten wasmore fragrant and delicious. The modified wheat gluten could help to improve the internalcellular uniform and delicate texture of bread.